This invention relates to thermal batteries, and in particular to the enclosure (container and header (or lid)) for thermal batteries.
Thermal batteries are a type of reserve battery having a long shelf life. Such batteries are ideal for uses where the battery will be stored for long periods of time (possibly many years) and then called upon to provide power in a highly reliable fashion. Thermal batteries have been used for years in many military applications, for example, to power the guidance systems on missiles.
Thermal batteries also can be used as a backup power source for emergency situations. For example, thermal batteries can be used as a backup power source in deep-sea applications to ensure that equipment located in remote locations such as at the ocean floor for a deep water oil drilling rig have a reliable power supply in the event of a loss of power from a primary power supply. For example, thermal batteries can be used as a backup power source for a blowout preventer that is provided on oil drilling equipment.
The typical thermal battery includes a stainless steel enclosure (container and lid (also called the header)) that encloses the components of the battery. Much care must be taken when assembling the battery to ensure that the electrical components within the enclosure do not contact the electrically-conductive stainless steel enclosure. For example, insulative material is provided around the electrical components to prevent contact with the stainless steel enclosure.
The batteries also include a number of terminals which extend through the enclosure (usually through the header) so as to make electrical contact with the battery cells and with the pyrotechnic squib that is used to activate the thermal battery. Glass seals are used to seal the terminals to the enclosure where the terminals pass through the enclosure.